CircStats (version 0.2-7)

watson.two: Watson's Two-Sample Test of Homogeneity

Description

Performs Watson's test for homogeneity on two samples of circular data.

Usage

watson.two(x, y, alpha=0, plot=FALSE)

Value

NULL

Arguments

x

vector of circular data measured in radians.

y

vector of circular data measured in radians.

alpha

significance level of the test. Valid levels are 0.001, 0.01, 0.05, 0.1. This argument may be ommited, in which case, a range for the p-value will be returned.

plot

logical value. If TRUE, an overlayed plot of both empirical distribution functions will be sent to the current graphics device. The default value if FALSE.

Details

Critical values for the test statistic are obtained using the asymptotic distribution of the test statistic. It is recommended to use the obtained critical values and ranges for p-values only for combined sample sizes in excess of 17. Tables are available for smaller sample sizes and can be found in Mardia (1972) for instance.

References

Jammalamadaka, S. Rao and SenGupta, A. (2001). Topics in Circular Statistics, Section 7.5, World Scientific Press, Singapore.

Examples

# Perform a two-sample test of homogeneity on two
# simulated data sets.
data1 <- rvm(20, 0, 3)
data2 <- rvm(20, pi, 2)
watson.two(data1, data2, alpha=0.05, plot=TRUE)
watson.two(data1, data2)